A Silver Spring company planning to build a long-awaited natural gas-fired electricity plant in Waldorf expects favorable outcomes in a pair of lawsuits that have further delayed the project, Competitive Power Ventures executives said Thursday.

Each of the lawsuits, one apiece filed in state and federal court, challenge an April 2012 order from the Maryland Public Service Commission requiring three major utilities that sell power in the state to buy electricity from the 661-megawatt plant, which is expected to cost more than $500 million, create between 350 and 400 temporary construction jobs and generate $128 million in revenue for Charles County. The plant will be built on Billingsley Road near the county landfill.

The project has been in the works since 2007, the same year the state stepped up efforts to increase its electrical generating capacity.

Years of delays followed as state regulators considered whether to require utilities to enter into long-term purchasing agreements with electricity generators.

In April 2012, citing the state’s electricity needs, the PSC issued an order requiring Baltimore Gas & Electric, Pepco and Delmarva Power to buy power from the plant. Construction was expected to begin late last year, with the plant set to be online by June 2015.

But shortly after the PSC’s order, the three utilities filed a lawsuit challenging the commission’s authority to require the purchasing contracts, said Don Atwood, a CPV vice president and the project’s construction manager.

Meanwhile, other electricity generators within the PJM Interconnection grid — the electricity transmission system spanning 13 states and Washington, D.C. — filed a federal lawsuit that has since been completed and is awaiting a judge’s decision, said Braith Kelly, CPV senior vice president of external affairs.

The company expects favorable outcomes in both cases, he said.

“It’s been delayed by a number of actions the utilities have taken,” Kelly said. “They’ve done everything they can to delay the project.”

The delay has led to the postponement of a $2 million company payment in lieu of taxes, or PILOT, to the county that is partially responsible for a projected $3.65 million shortfall in property tax revenue for the current fiscal year, budget officials told the county commissioners Tuesday.

The county is estimating $189.8 million in property tax revenue for fiscal 2013, nearly 2 percent short of the $193.5 million originally budgeted.

“This is due to a delay in the CPV PILOT payment, as you all are aware,” Chief of Budget David M. Eicholtz said.

The company’s PILOT payments were supposed to begin with $2 million in fiscal years 2013 and 2014, county spokeswoman Donna Fuqua said in an email. The county is currently anticipating a two-year delay in the payment, she added.

“At the end of the day, we do not expect there to be a significant delay” in the project or the payment, Candice Kelly said.

Commissioner Ken Robinson (D) said the county has received “encouraging news” about construction beginning soon.

“Certainly no dire consequences from this, whatsoever,” he said.

Both company executives intimated that the delay in no way threatens the project.

“We look forward to getting this project into construction and getting the results both the county and CPV want,” Atwood said.

Once operational, the plant is expected to support 30 permanent jobs and reduce sulfur, nitrogen and carbon dioxide emissions by 65 to 99 percent compared to oil and coal-fired plants.

The plant also will use reclaimed sewage water to cool itself, reducing the annual nitrogen and phosphorous discharges into the Potomac River by up to 18,700 and 1,110 pounds, respectively.